Queensland foster father Rick Thorburn will spend at least 20 years behind bars after killing the young girl he was meant to love and protect.
Thorburn has been jailed for life, meaning he'll spend at least two decades behind bars, for killing his 12-year-old foster daughter Tiahleigh Palmer and dumping her body in a Gold Coast river in 2015.
Thorburn wiped away tears as he replied "guilty" to charges of murder, interfering with the 12-year-old's corpse, perjury and attempting to pervert the course of justice.
Just metres away, Tiahleigh's biological mother, Kiwi Cindy Palmer finally got the admission she has waited for years - that the man trusted with caring for her daughter actually snuffed out her life.
In sentencing Thorburn, Supreme Court Justice David Boddice said his crimes were cold and callous. "You murdered this defenceless child who relied on you for protection," he said
Palmer, pledged in 2016 that her daughter's death will not be in vain.
She thanked police for their tireless work throughout the 11-month investigation into her daughter's murder and said the time had come to get "justice for Tiahleigh".
Thorburn had concocted a web of lies to cover up his heinous crime, and those of his wife and two sons who have already been jailed for their complicity.
One of those sons, Trent, had confessed to his parents that he'd been having sex with his foster sister, and feared she might be pregnant.
Rick Thorburn, fearing his son could be charged, told his family he was going to take care of things, the Brisbane Supreme Court was told today.
Six days after Thorburn said he dropped Tiahleigh safety at school on October 30, 2015, fishermen found a girl's badly decomposed body on the banks of the Pimpama River. It was later confirmed to be Tiahleigh.
Sometime between 8pm and 10pm on October 29, Rick Thorburn murdered the 12-year-old, the court was told.
He then went on a mission to dispose of her body and was covered in dirt when he returned and told his family: "It's done."
The court heard they maintained a lie about Tiahleigh running away before her body, unclothed but for her underpants, was found in the river.
An autopsy was conducted but due to the state of her body a cause of death was never determined, the court heard. The only noticeable injury was a bruise on her skull.
During the police investigation, all family members gave the same false version of events but detectives were suspicious and bugged the family's home, listening to their conversation for about a month.
The discussions, combined with the motive of keeping Tiahleigh quiet about Trent having sex with her - led to the family's arrest.